Systems and methods for transmitting communications in networks and between networks are well known. For example, cellular messages may be received via a cellular network, converted into packets of information, and transmitted over a packet data network (PDN) to various destinations.
Various types of protocols are used to enable the transmission of messages across these networks. The protocols may be for signaling or actually sending the desired information. One example of a signaling protocol is the Session Initiation Protocol (SIP) described in IETF RFC 3261, which may be used to transmit and receive messages across PDN networks. SIP is often used in Internet conference, telephony, and instant messaging applications. In one example of a SIP message, an INVITE message is used to invite a user or a unit to participate in a call while other SIP messages (such as RINGING, OK, ACK and BYE) are required to control the call. In another example, a REGISTER message is used to register a mobile unit at a particular IP address in the network.
A system conforming to the SIP protocol utilizes proxies or agents to handle various processing functions. For example, a proxy may create a contact alias that identifies a mobile unit. This contact alias may be created when the unit sends a REGISTER message to the proxy. After processing, all future SIP messages directed at the mobile unit, for instance all INVITE messages for the mobile unit, will be sent to the proxy.
One problem that arises in many of the above-mentioned systems is that the amount of information that is transmitted between points in the network often becomes great thereby significantly slowing the operation of the network. For example, the number of INVITE messages may multiply during the course of network operation. If the level of message loading becomes large, a significant reduction of network performance is known to occur. This problem is particularly severe in wireless networks, such as cellular telephony systems because data rates at the air interface are generally lower than the rest of the network. Certain techniques, for instance message compression, are used in computer networks to reduce message size and increase network performance. However, current systems do not combine the use of an alias together with message compression. This results in network congestion and the slowing of network operation.
Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of various embodiments of the present invention. Also, common but well-understood elements that are useful or necessary in a commercially feasible embodiment are typically not depicted in order to facilitate a less obstructed view of these various embodiments of the present invention.